Crystal-controlled oscillator



July 23, 1929.

I. F. BYRNES 1,722,196

CRYSTAL CONTROLLED 0S CILLATOR Filed Sept. l, 1926 I ventor-z Irving F Barnes;

Hi5 Attorney Patented July 23, 1929.

; Nl'iE- STTES COMPANY, A season-Arron on NEW YORK.

1 oRYsi'An-oouTEoLLEn OSCILLATOR.

Application filed September 1, 1926. Serial No. 133,033.

My invention relates to'oscillation generators wherein a piezo electric element is utilized to control the frequency at which current is supplied through a space discharge device, and has for its principal object the provision V of an improved arrangement which minimizes or obviates the effect of the space discharge device capacitance on the vibration frequency of the piezo electric element.

It is known that an oscillating piezo elec tric element, such as a slab or disk of quartz,

will continue to oscillate when subjected to voltage at a frequency corresponding to its free vibration period. When utilizing a piezo electric element to predetermine the oscillation frequency of a circuit comprising the anode and cathode of a space discharge device, oscillation is apparently started in the piezo electric crystal by the relatively small irregularities in the electron emission of the cathode of the device. These slight stresses and determining the anode current frequency of the space discharge device.

VJhen a piezo electric element is utilized to predetermine the frequency at which currentis delivered to a circuit, however, difficulty is encountered due to the effect produced on the operation of the piezo electric element by the capacity between the grid and cathode of the space discharge device. In accordance with my invention, this, effect is greatly reduced by the provision of anarrangement wherein the grids and cathodes of a plurality of space discharge devices are connected to the piezo electric elementin series with one another.

My invention will be better understood from the following description When considered in connection with the accompanying drawing and its scope will be pointed out in the appended claims. 7

The drawing shows an oscillation generator wherein my invention has been embodied Y IRVING F. BYRNES, or SCEENECTADY, NEW YonK, Assrenon To enivnnannrnc'rnrc This generatorcompri-ses a pair of space discharge devices land-2, a source of cur- I 1 rent shown as a battery 3, load terminals 4 which are connected to the output circuit of the devices 1 and 2 through a transformer 5, and a piezo electric element 6 which'is connected through impedance devices shown as resistors 7 and 8 to the input circuits of the devices 1 and 2. The negative terminal of the source 3 is connected to the cathodes of the devices 1 and 2 and to a conductor which interconnects the opposite ends of the resis- I tors 7 and 8 and the positive terminal of this source is connected to the anodes of devices 1 and 2 through the opposite halves of a primary winding 10 of the transformer 5. g A

variable condenser 11 may be provided for tuning the output circuit of the devices 1 and 2 to a frequency which is approximately the same as the resonance frequency of the ele ment 6 which operates to maintain the output frequency within very narrow limits. It

will be observed that the grid and cathode of the device lare interconnected through the resistor 7 and that the grid and cathode of the device 2 are interconnected through the I resistor 8.

Under'these conditions, the piezo electric element 6, the cathode and grid of the device 1 and the cathode and grid of the device 2 are all connected in series with one another, the capacitance interposed in the seriescircuit including the piezo electric element is reduced to a value which is but one-half that between the grid and cathode of a single space discharge device, and the effect produced on the operation of these elements by the capacities between the grids and cathodes of the space discharge devices, is greatly reduced.

The embodiment of the invention illustrated and described herein has been selected for the purpose of clearly setting forth the principles involved. It will be apparent, howmentc0mprising a plurality ofterminals, a

connected in'a series circuit including said element; v 2. The combination of a piezo electric element'romp'rising .a plurality of terminals;

plurality of space discharge devices each'pro of said devices.

3. The combination of apiezoelectric eleplurality of space discharge devices each provided with a grid connected to a different one of said'terniinals and with a cathode, an impedance-elementconnected between'said ter minalsg and means'arran'ged to interconnect the cathodes of said devices with said impedance element" at a point intermediate to its connections to said terminals.

In Witness whereof, Ihave hereunto set my 20 

